Here are a few commands for running the Windows Update Agent from a command line:
Force detection of updates:
wuauclt /detectnow
Force reporting status to an Windows Update Server:
wuauclt /r /ReportNow
Stop and start the automatic updates service:
net stop wuauserv
net start wuauserv
To help troubleshooting here’s where the log is normally.
%systemroot%\WindowsUpdate.log